You have to set threshold as the number of milliseconds you want to delay sending the second SMS. You've set it as 0, so there won't be any delay! I suggest you set it to 10,000 to give a 10 second delay.
You have to set threshold as the number of milliseconds you want to delay sending the second SMS. You've set it as 0, so there won't be any delay! I suggest you set it to 10,000 to give a 10 second delay.